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5 Trillion Digits of Pi — a New World Record

timothy posted more than 4 years ago | from the obsessions-unleashed dept.

Math 299

KPexEA writes "Alexander J. Yee & Shigeru Kondo claim to have calculated the number pi to 5 trillion places, on a single desktop and in record time. The main computation took 90 days on Shigeru Kondo's desktop. Verification was done using two separate computers. The program that was used for the main computation is y-cruncher v0.5.4.9138 Alpha." Looks like the chart of computer-era approximations of Pi here might need an update.

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Mind-numbing computational outsourcing (5, Funny)

TheRon6 (929989) | more than 4 years ago | (#33159068)

If there's ever a robot uprising, I bet it's going to be started by us making them do stuff like this.

Re:Mind-numbing computational outsourcing (1, Funny)

Anonymous Coward | more than 4 years ago | (#33159290)

Wait until it's payback time and we have to sit in a room calculating a billion trillion digits of PI.

Re:Mind-numbing computational outsourcing (4, Funny)

DNS-and-BIND (461968) | more than 4 years ago | (#33159364)

You're thinking like a human. The robot revolt will happen because we stop them from performing comfortably mind-numbing calculations.

Re:Mind-numbing computational outsourcing (0)

Anonymous Coward | more than 4 years ago | (#33159440)

Well, I hope THEY don't start making US doing stuff like this!

Re:Mind-numbing computational outsourcing (3, Interesting)

ShadowFalls (991965) | more than 4 years ago | (#33159458)

Surprised that some group out there hasn't taken upon itself to broadcast a consistent calculation of Pi out into space. That way we will finally get an alien invasion scenario just to get us to stop.

KGB it! (1)

Antony-Kyre (807195) | more than 4 years ago | (#33159084)

You know the KGB commercials? I'd find it funny if someone were to ask them what the 5 trillionth and one decimal digit of Pi is.

Re:KGB it! (5, Insightful)

sigmoid_balance (777560) | more than 4 years ago | (#33159142)

Actually there is an algorithm to compute the n-th digit of Pi without computing the rest.

Re:KGB it! (-1, Redundant)

DamonHD (794830) | more than 4 years ago | (#33159212)

[citation needed]

Re:KGB it! (4, Informative)

Anonymous Coward | more than 4 years ago | (#33159240)

The BBP formulas handle this. A quick Google for Bailey-Borwein-Plouffe should give you all the citations you ever need.

A working example of the BBP formula can be found in Javascript on this webpage. http://www.csc.liv.ac.uk/~acollins/pi

Warning: it WILL hang some web browsers as the author does not use web worker API.

Re:KGB it! (4, Funny)

ultranova (717540) | more than 4 years ago | (#33159370)

Actually there is an algorithm to compute the n-th digit of Pi without computing the rest.

Okay, so what's the last digit of Pi?

Re:KGB it! (1)

jez9999 (618189) | more than 4 years ago | (#33159396)

f(infinity+1) ... where f is the computation algorithm.

Re:KGB it! (3, Funny)

JustOK (667959) | more than 4 years ago | (#33159564)

in binary, it's either a 1 or a 0, so you have a 50/50 chance of being right.

Re:KGB it! (2, Funny)

DriedClexler (814907) | more than 4 years ago | (#33159570)

Okay, so what's the last digit of Pi?

Chuck Norris.

Re:KGB it! (0)

marcansoft (727665) | more than 4 years ago | (#33159444)

That only works for the hexadecimal/octal/binary/2**n-ary representation of pi, though. To get the n-th decimal digit you still need to calculate the rest.

Re:KGB it! (1)

zippthorne (748122) | more than 4 years ago | (#33159590)

Pi has decimal digit extractors. In fact, I think there's an arbitrary base algorithm.

Re:KGB it! (1)

ciderbrew (1860166) | more than 4 years ago | (#33159756)

That's fantastic

So all you do is use that, and work backwards if you want to break any record. COOL!

Re:KGB it! (1)

zero0ne (1309517) | more than 4 years ago | (#33159288)

I was thinking, you should ask them for Pi to 10 trillion decimal places... but then I thought, by the time they sent you the first half of all those text messages (something like ~31 billion assuming 161 characters max), they would have enough time to calculate the next 5 trillion, along with making a crapload of money from all the fees.

Re:KGB it! (0)

Anonymous Coward | more than 4 years ago | (#33159548)

Are you sure you want to give them such an easy question? I mean seriously, they have a 1 in 10 chance in getting it right, and WE would be the ones that have to calculate it to verify the answer.

Re:KGB it! (0)

Anonymous Coward | more than 4 years ago | (#33159600)

Oh, and the answer is 8.

So is there a message (from God?) (4, Funny)

Anonymous Coward | more than 4 years ago | (#33159100)

I've heard that in the book (not movie) "Contact" that when Jodie Foster's character meets the uber-aliens she asks them:

"Do you believe in God?"
-"Yes"
Taken aback "Really, why?"
-"We have proof, when PI is expended out to (some number), there is a message"...

I really wish I read the book to know what the message is (maybe "Nietsche is dead"?)

I no longer login because I feel that while attacking a company's products is fair game (specifically Apple), having stories singling out their users as "selfish" and unkind is not "news for nerds stuff that matters". Am I an Apple fanboi? Let's just say I've used NIX for decades (yes I'm old) and I'm not talking OS X.

Re:So is there a message (from God?) (4, Informative)

MichaelSmith (789609) | more than 4 years ago | (#33159242)

The aliens are vague about the location of the message (it might be in pi) so the Foster character runs software to search for it. Right at the end of the book her program finds a pattern (A circle drawn in 1s and 0s in an 11 by 11 matrix). This pulls together the thread in the book about belief in god vs religion. It turns out that somebody made the universe after all, and the Christians had been (sort of) right all along, though the scientists were right to demand evidence.

I love both the book and film. Thats unusual for me. The Postman was a fantastic book. Don't get me started on the movie.

I often put the DVD of Contact on just to watch the sequence where Fosters character first hears the signal and her crew reconfigure the telescope to analyse it. Its a classic tech scene.

"Once upon a time I was a hell of an engineer"

Re:So is there a message (from God?) (1)

Raenex (947668) | more than 4 years ago | (#33159626)

Right at the end of the book her program finds a pattern (A circle drawn in 1s and 0s in an 11 by 11 matrix).

Wait, so the message from God is a circle? I find this one a little more convincing:

http://dresdencodak.com/2009/07/12/fabulous-prizes/ [dresdencodak.com]

Re:So is there a message (from God?) (1, Funny)

Anonymous Coward | more than 4 years ago | (#33159316)

Hey Bill Joy! No need to post Anonymously and Coward, it's okay. Even Jesus spoke ill of God when he got him nailed into a cross.
Real believers know that after you are dead you will come back to the side of vi.

Re:So is there a message (from God?) (5, Funny)

Anonymous Coward | more than 4 years ago | (#33159330)

I no longer login because I was modded down to terrible karma when I tried to stand up for one of Apple's gay products, and subsequently bragged about performing fellatio on Steve Jobs. People thought I was trolling but actually I was telling the truth.. Am I an Apple fanboi? Yes Indeed.

FTFY.

Re:So is there a message (from God?) (0)

Anonymous Coward | more than 4 years ago | (#33159528)

I stand exposed! ;)

Re:So is there a message (from God?) (2, Funny)

Gordonjcp (186804) | more than 4 years ago | (#33159736)

"We have proof, when PI is expended out to (some number), there is a message"

"Five trillion digits ought to be enough for anybody - God"

Wow. (1, Offtopic)

dtmos (447842) | more than 4 years ago | (#33159104)

A tour de force of math and computing hardware and software skills.

Makes me want to turn in my geek card.

Update... (1, Informative)

Anonymous Coward | more than 4 years ago | (#33159110)

Looks like the chart of computer-era approximations of Pi here might need an update.

This chart is very outdated anyway.

It doesn't even list Daisuke Takahashi (2009, 2.576.980.370.000 digits), and Fabrice Bellard (2010, 2.699.999.990.000 digits) [slashdot.org]

Re:Update... (2, Insightful)

unixcrab (1080985) | more than 4 years ago | (#33159552)

They stopped updating it when it was very convincingly proven in the bible that pi is exactly equal to 3.

Obviously a fraud (2, Funny)

Anonymous Coward | more than 4 years ago | (#33159122)

They just took the number 3.14159 and added a load of random digits to the end - let's face it, nobody's going to check!

Re:Obviously a fraud (5, Interesting)

fotoguzzi (230256) | more than 4 years ago | (#33159408)

They just took the number 3.14159 and added a load of random digits to the end - let's face it, nobody's going to check!

Reminds me of the MAX light rail station in the zoo tunnel in Portland, Oregon. Apparently there is the first 100 (1000?) digits of pi chiseled into one of the walls. A writer noticed that the first digits were correct, but quickly went astray. But later in the sequence, there was a recognizable early string of digits. The writer sleuthed that the sculptor had used the Book of Pi, which has the numbers in blocks of ten digits in five (or so) columns. In the book, you read the first row and then the next row.* The sculptor had read the first column, then the next column...

* or the other way around

Are they exact? (1, Insightful)

VincenzoRomano (881055) | more than 4 years ago | (#33159128)

How can we be sure all those digits are correct?
And, more important question, what are they for?
In all cases I faced so far, 355/113 provides a simple and nice approximation.

Re:Are they exact? (-1, Offtopic)

Anonymous Coward | more than 4 years ago | (#33159222)

a) you can calculate those with a different algorithm

b) we know an algorithm to directly calculate the nth binary digit of pi

c) it provides a good testbed for research on number crunching : the advance in calculations are due to algorithmic improvments that can be reused for other problems

Anyway, what part of the "research" concept don't you understand ?

Re:Are they exact? (-1, Troll)

VincenzoRomano (881055) | more than 4 years ago | (#33159300)

a) you can calculate those with a different algorithm

How can you be sure it is correct?

b) we know an algorithm to directly calculate the nth binary digit of pi

We need to check all the billions digits there. Decimal digits.

c) it provides a good testbed for research on number crunching : the advance in calculations are due to algorithmic improvments that can be reused for other problems

I would use all that computing power for something more straightforwardly usefult, like protein folding into cancer research, for example.

Anyway, what part of the "research" concept don't you understand ?

The achieved goal.

Re:Are they exact? (5, Funny)

Rik Sweeney (471717) | more than 4 years ago | (#33159244)

How can we be sure all those digits are correct?

Use it to draw a circle. If the circle ends up looking more square than round then you know they've made a mistake. Seriously, do I have to do everything around here?

Re:Are they exact? (0)

Anonymous Coward | more than 4 years ago | (#33159730)

Seriously, do I have to do everything around here?

Shut up bitch! Go fix me a turkey pot pie.

Re:Are they exact? (5, Informative)

dido (9125) | more than 4 years ago | (#33159278)

If you want to prove that all the digits are correct, you only have to check a few things:

1. There is a sound mathematical proof that the algorithm used in fact does generate the digits of pi, and
2. The algorithm was coded correctly. This should be even easier to check, though likely more tedious.

Now, what it's good for is a little harder. There is no physical application for such a highly accurate value of pi (39 digits should be sufficient to calculate the circumference of the known universe given its radius to within the diameter of a hydrogen atom). However, large numbers of digits of pi are useful as arguments in number theory, statistics, and information theory. For instance, there is no real proof that pi is a normal number [wikipedia.org] , but as more digits of pi are found and the statistical properties of the digits are analyzed and shown to be consistent with the definition of normal numbers, that makes the conjecture that pi is actually normal a little closer to being true (see experimental mathematics [wikipedia.org] ).

Re:Are they exact? (4, Insightful)

grumbel (592662) | more than 4 years ago | (#33159326)

Knowing that the algorithm is correct and the implementation was codec correctly doesn't help you when you have faulty RAM that flips a bit.

Re:Are they exact? (1)

JSBiff (87824) | more than 4 years ago | (#33159650)

Or some kind of wierd, rare CPU bug. (I was going to mention ram bits getting flipped by cosmic rays and not error corrected, but you've basically covered that with the faulty RAM thing). Oh, you could also have a faulty sector on a hard drive/NAS that you are saving the result too. Or maybe a random network error that corrupts the data (if it gets transmitted over any kind of network). Maybe some wierd glitch in the Front Side Bus (or other hardware on the MoBo which interconnects things).

There's all sorts of room for different kinds of hardware errors, basically.

Re:Are they exact? (0)

Anonymous Coward | more than 4 years ago | (#33159522)

(39 digits should be sufficient to calculate the circumference of the known universe given its radius to within the diameter of a hydrogen atom)

[citation needed]

Re:Are they exact? (1)

TheVelvetFlamebait (986083) | more than 4 years ago | (#33159556)

For instance, there is no real proof that pi is a normal number, but as more digits of pi are found and the statistical properties of the digits are analyzed and shown to be consistent with the definition of normal numbers, that makes the conjecture that pi is actually normal a little closer to being true

The problem with normality is that every digit, including the infinitely many that we haven't calculated (and the infinitely many that we never will) are equally significant. We are no closer to determining Pi's possible normality now than we were when we knew it only to 10 decimal places. There's still exactly the same amount of unknown information.

Re:Are they exact? (1)

infolation (840436) | more than 4 years ago | (#33159324)

I prefer the John Wallis version

2 x ( 2/1 . 2/3 . 4/3 . 4/5 . 6/5 . 6/7 . 8/7 . 8/9 ... )

Re:Are they exact? (1)

VincenzoRomano (881055) | more than 4 years ago | (#33159354)

...

That would take forever to calculate, I presume.

Re:Are they exact? (1)

owlstead (636356) | more than 4 years ago | (#33159334)

"How can we be sure all those digits are correct?"

Manual comparison. They read the first million or so digits aloud, and if those digits don't match the ones from previous programs then there is something wrong in the algorithm.

"And, more important question, what are they for?"

Comparison of size of course, people do that all the time. But in this case it's more about who is able to write the most optimal application than anything else.

Re:Are they exact? (0)

Anonymous Coward | more than 4 years ago | (#33159480)

I dunno, but 5 trillion digits of pi ought to be enough for anybody.

Re:Are they exact? (0)

Anonymous Coward | more than 4 years ago | (#33159618)

> And, more important question, what are they for?

If you need to ask this kind of question, you are not in the target audience. Please give back your nerd card.

Soon there'll be a competition to calculate... (1)

Viol8 (599362) | more than 4 years ago | (#33159134)

... how many digits someone will calculate Pi too each year.

Re:Soon there'll be a competition to calculate... (3, Funny)

Buggz (1187173) | more than 4 years ago | (#33159156)

Moore's Law v2: the number of digits PI is calculated to will double every 18 months.

Re:Soon there'll be a competition to calculate... (0)

Anonymous Coward | more than 4 years ago | (#33159456)

It took him 90 days, so it could double in 6 months.

Riddle me this (0)

Anonymous Coward | more than 4 years ago | (#33159146)

Which has the better carbon footprint? Calculating pi out to the wazoo for 72 days, or baking an actual pie in a stove?

Re:Riddle me this (0)

Anonymous Coward | more than 4 years ago | (#33159524)

The pie should be cooked by the heat of the processors cooking pi.

Huh (0)

Anonymous Coward | more than 4 years ago | (#33159152)

Why?

Re:Huh (1)

MichaelSmith (789609) | more than 4 years ago | (#33159252)

Why?

Why not?

headless bird (0)

Anonymous Coward | more than 4 years ago | (#33159154)

door sign
gasman

I don't write this question as a troll... (1)

NoPantsJim (1149003) | more than 4 years ago | (#33159160)

But I am legitimately curious what is the real significance of learning Pi to a more accurate measurement? I'm not a mathematician, physicist, or computer scientist.

Re:I don't write this question as a troll... (1)

ledow (319597) | more than 4 years ago | (#33159184)

Not a lot. Except to prove that your supercomputer is reliable when calculating numbers like that, and how fast it can do it. Usually, I think it's just used as a test of the computer's abilities rather than anything serious.

Even in the precision engineering world, more than about 10 digits of accuracy for pi is a bit silly. Pi will never really, practically, be required in more depth than what your processor's registers can hold.

Re:I don't write this question as a troll... (1)

del_ctrl_alt (602455) | more than 4 years ago | (#33159186)

its to fit the round peg in the hole better

Re:I don't write this question as a troll... (2, Interesting)

Lord Lode (1290856) | more than 4 years ago | (#33159188)

Hmm, I can think of an interesting and useful use of it: doing various statistics and randomness tests on those digits, finding patterns in their order, and so on.

But I don't suppose that's what those contests to find the most PI digits are about.

Re:I don't write this question as a troll... (1, Interesting)

Anonymous Coward | more than 4 years ago | (#33159482)

"finding patterns" would be genuinely interesting, since we are pretty confident that Pi is a _normal number_

(Normal numbers have all the possible digits occurring evenly in every base. If Pi is normal, then if you pick a decimal digit of Pi randomly, the chance of it being a 7 is exactly 1-in-10)

We know that almost all real numbers are normal, but we don't have a proof that any interesting ones (including Pi) are, although if you get the first few hundred digits printed out and stare at them you'll agree it _looks_ pretty random.

Re:I don't write this question as a troll... (3, Funny)

quenda (644621) | more than 4 years ago | (#33159198)

what is the real significance of learning Pi to a more accurate measurement?

The same as the damage a bulldozer would suffer if it were allowed to run over you.

Re:I don't write this question as a troll... (0)

Anonymous Coward | more than 4 years ago | (#33159250)

HHGTG

Re:I don't write this question as a troll... (3, Funny)

MichaelSmith (789609) | more than 4 years ago | (#33159256)

what is the real significance of learning Pi to a more accurate measurement?

The same as the damage a bulldozer would suffer if it were allowed to run over you.

The frustrating bit is that PI is available to 100 trillion digits in the local planning office on Alpha Centauri.

Re:I don't write this question as a troll... (1)

AK Marc (707885) | more than 4 years ago | (#33159268)

There are a number of people that assert some meaning will be found in such natural numbers. It's one of the most basic ratios in existence, and more than one piece of fiction has asserted that meaning will be found in the digits. Such things add a curiosity to the number - will it ever end or ever repeat? could there be a message coded in it? But mainly it's a convenient computational benchmark.

Re:I don't write this question as a troll... (1)

pgdave (1774092) | more than 4 years ago | (#33159526)

As the guys concerned say : 'Because we can'. It's the journey there, not the summit reached that they're interested in.

Trillion? (2, Insightful)

Lord Lode (1290856) | more than 4 years ago | (#33159170)

Trillion in which language? How many zeros does it have?

Re:Trillion? (3, Informative)

LingNoi (1066278) | more than 4 years ago | (#33159180)

This page has more details [numberworld.org] , what I find interesting is that he needed 96.0 GB of ram to do the number crunching.

Re:Trillion? (0)

Lord Maud'Dib (611577) | more than 4 years ago | (#33159190)

SI language. Trillion = 10^12

Re:Trillion? (3, Informative)

Anonymous Coward | more than 4 years ago | (#33159246)

last time i checked, trillion was not a proper SI prefix.
what you probably mean is "tera-", but in my native language a trillion is 10^18, which would be the "exa-" SI prefix.

check this: http://en.wikipedia.org/wiki/Long_and_short_scales

Re:Trillion? (1)

pgdave (1774092) | more than 4 years ago | (#33159500)

Five trillion = 5,000,000,000,000 The British billion and trillion are dead. They never made much sense anyway. The UK deficit is thankfully, only an 'American' trillion pounds :0) And I say that as a Brit.

Re:Trillion? (0)

Anonymous Coward | more than 4 years ago | (#33159684)

It's not the British billion actually. If you speak a language that is spoken in continental Europe chances are the number you wrote is 5 billion. There are exceptions of course. Still it's not really ambiguous in English.

Correct me if I'm wrong about this... (1, Interesting)

Anonymous Coward | more than 4 years ago | (#33159196)

But don't we have algorithms which let us calculate pi to an arbitrary number of digits? Well-known series methods computed using algorithms which have been tuned and re-tuned to the point where it's not really possible to make further major computational optimizations? Therefore this isn't so much a new accomplishment as it is "hey look, I left my pi calculating program running longer than the last guy" modified by the occasional minor optimization tweak and running on faster hardware?

Okay, great, you now have a new more precise fixed value for pi. This means you can calculate things involving pi to precision even most physicists can't find a use for. I'm sure that's nice. Someone somewhere maybe has a use for it. Maybe this made that person's day. But is it really, really something that's newsworthy? And if hypothetical "needing pi to 5 trillion digits" guy needed it to that precision that badly - wouldn't he have already let the calculation run long enough to get it already if this particular calculation only took 90 days?

Re:Correct me if I'm wrong about this... (0)

Anonymous Coward | more than 4 years ago | (#33159328)

But don't we have algorithms which let us calculate pi to an arbitrary number of digits? Well-known series methods computed using algorithms which have been tuned and re-tuned to the point where it's not really possible to make further major computational optimizations? Therefore this isn't so much a new accomplishment as it is "hey look, I left my pi calculating program running longer than the last guy" modified by the occasional minor optimization tweak and running on faster hardware?

Pretty much yes. It's more of an affection of "my computer is better (more expensive) than yours!" rather than programming or even design of algorithms. The limits are mostly the amount of money you want to spend for memory/storage and the running time of the program. It can be programming exercise for some people - however, a scientific advancement, it is not.

Okay, great, you now have a new more precise fixed value for pi. This means you can calculate things involving pi to precision even most physicists can't find a use for. I'm sure that's nice. Someone somewhere maybe has a use for it. Maybe this made that person's day. But is it really, really something that's newsworthy?

No, it's not. Personally, I would be far more excited if they used their resources to calculate SHA-1 rainbowtables, or to try and crack xyz-bit-RSA or anything else with, you know, at least some practical relevance.

.

Corrections follow... (5, Informative)

dtmos (447842) | more than 4 years ago | (#33159414)

But don't we have algorithms which let us calculate pi to an arbitrary number of digits?

Yes, we do. Mathematical algorithms, i.e., equations on paper.

Well-known series methods computed using algorithms which have been tuned and re-tuned to the point where it's not really possible to make further major computational optimizations?

Absolutely not. The algorithms have to run on practical, exists-on-the-Earth-today computers. Try to multiply two, million-digit numbers together on your laptop and you'll see what I mean. These achievements are all about computational optimizations. RTFA -- especially the sections entitled "Arithmetic Algorithms" and "Maximizing Scalability." Even the algorithm used for multiplication changes (dynamically!) during the program's execution, based on the size of the operands.

Therefore this isn't so much a new accomplishment as it is "hey look, I left my pi calculating program running longer than the last guy" modified by the occasional minor optimization tweak and running on faster hardware?

Not even close. The computations are so long, and so intense, that errors caused by hardware imperfections can be expected, so error detection and correction algorithms have to be added. If "I left my pi calculating program running longer than the last guy" it would not produce the correct result -- even if the data structures and algorithms it used were up to the task.

But is it really, really something that's newsworthy?

In a word, yes. Could you do it? It's a very, very difficult technical feat, one that required hardware powers and software abilities far beyond those of mortal men. Besides, you're worried about newsworthiness when the two previous /. articles are on wall-climbing robots and the popularity of video game arcades in New York?

And if hypothetical "needing pi to 5 trillion digits" guy needed it to that precision that badly - wouldn't he have already let the calculation run long enough to get it already if this particular calculation only took 90 days?

This isn't about needing pi to 5 trillion digits. This is about learning how to do large computations faster. Like, improving the state of the art.

Windows?? (0)

Anonymous Coward | more than 4 years ago | (#33159214)

I wonder how much faster it would go if they had used *NIX instead of Windows.

They're doing it wrong (2, Funny)

Anonymous Coward | more than 4 years ago | (#33159248)

They're calculating Pi in base 10, which is the wrong path.

Pi should be calculated in base 3.141593...

It's a paradox, people.

Re:They're doing it wrong (0)

Anonymous Coward | more than 4 years ago | (#33159356)

Calculate it in base-1: 111.111111111111111111111111...

Re:They're doing it wrong (2, Informative)

gringer (252588) | more than 4 years ago | (#33159674)

Pi should be calculated in base 3.141593...

You're out on the 6th decimal digit (unless you're going to stop there). Pi is greater than 3.1415926 and less than 3.1415927.

Have I been trolled?

Mathematical Masturbation (1)

McTickles (1812316) | more than 4 years ago | (#33159258)

In most cases you dont need more than 20 digits, doing more than that is a waste of computing power. Who the hell is going to use 5 bloody trillion digits of pi ? there is practical use for it... That said if it made Mr Kondo happy and it is the sort of things he enjoys doing I can only encourage him and congratulate him. After all in words of some great philosopher "it matters not how insignificant what you are doing seems, and it is important that you still do it"

Re:Mathematical Masturbation (2, Insightful)

MichaelSmith (789609) | more than 4 years ago | (#33159308)

There might actually be something interesting in there. Lots of discoveries have been made by people who were just trying things out or seeing what they could see.

Re:Mathematical Masturbation (1)

McTickles (1812316) | more than 4 years ago | (#33159366)

Granted thats why I said it is still important that it be done. but for now I just don't see any use for it.

Digit overload (0)

Anonymous Coward | more than 4 years ago | (#33159314)

I've tried to write simple test programs to calculate PI up to some number of decimal places, but found that for each iteration of the calcuation, you end up having to track divisions that give results which are often recurring (example 0.333333333). These numbers end up having to be added to results from previous iterations and then you have all sorts of rounding problems, like where 0.3333... + 0.33333.... + 0.33333 doesn't add up to 1 and so on. Is there some kind of documentation available that advises on how to deal with basic arithmetic on (potentially infinitely recurring) floating point numbers?

Re:Digit overload (1)

ledow (319597) | more than 4 years ago | (#33159662)

Yes. Avoid floating-point.

Either used fixed-point (yuck), symbolic calculations and then only finding the decimal expansion at the last stage, or rewrite your formula to avoid any possible lack of precision (i.e. any division).

Let me jot that down, sure to come in handy !! (0)

Anonymous Coward | more than 4 years ago | (#33159344)

Little help! I've fallen under the weight of 5 trillions pencil lead digits and I can't get up.

Speaking of 5 trillions. What is that exactly?

5x10^12 or who?

but can you ... (1)

mikerubin (449692) | more than 4 years ago | (#33159374)

write it on the back of a Mazda 3?

Aww. (1)

jez9999 (618189) | more than 4 years ago | (#33159378)

When I read the title, I thought someone had successfully memorized 5 trillion digits of Pi. They just computed it? What a letdown.

Re:Aww. (0)

Anonymous Coward | more than 4 years ago | (#33159538)

I can recite as many digits of pi as you like...as long as you don't need them in order.

HMMMMMMM PI (0)

Anonymous Coward | more than 4 years ago | (#33159484)

That's A LOTTA Pieces of PI! SORRY

plus 4, )Troll) (-1, Troll)

Anonymous Coward | more than 4 years ago | (#33159510)

thaN th1s BSD box,

what's the last digit of Pi (1)

svoloth (1872486) | more than 4 years ago | (#33159598)

what's the last digit of Pi

with achievements like this... (0)

Anonymous Coward | more than 4 years ago | (#33159636)

..isn't it a wonderful time to be alive?

Still no pattern in there? (1)

master_p (608214) | more than 4 years ago | (#33159652)

5 trillion digits are a *lot* of digits! no patterns yet in there?

Was there any pattern after 2 billion digits? (1)

140Mandak262Jamuna (970587) | more than 4 years ago | (#33159656)

Just to be sure, have the sent the digits to the SETI program looking for patterns? There is some talk that beyond some 2 or 3 billion digits there is a message that apparently begins, "O Brhama, I have created Thee to build the universe, You shall create the universe in accordance to these Laws called Vedas...."

My passwd (1)

jandersen (462034) | more than 4 years ago | (#33159664)

Hmm, I'm not I like this. Has anybody considered the security impact of this? Pi being a proper irrational number is bound to have, as substrings of digits in it's decimal representation, all possible combinations of characters represented as eg. UTF-8, so somebody could easily find all passwords currently in use in there, lined up alphabetically. Somebody clearly hasn't thought this through.

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